Furnace control device



y 1933- H. F. FERGUSON 1,908,702

FURNACE CONTROL DEVI CE Filed March 9, 1932 2 Sheets-Sheet l Fig.7

W%\fz m May 16,- 1933. I H F, FERGUSON 1,908,702

FURNACE CONTROL DEVI C E Filed March 9, 1952 2 Sheets-Sheet '2 Z? 1 Z9 l J I) Z0 Z5 Howard FFbiyu-mn w 14 MKKQSW I I W Patented May 16, 1933 summon CONTROL nnvron Application filed. March 9,

My invention relates to a device for regulating and controlling a furnace or the like although not necessarily restricted to this use.

An important object of my invention is the provision of a device of this character which is automatic in operation and which will effectively regulate a furnace.

Another object of my invention is to provide a device of this character which may be readily attached to various types of furnaces, which'is inexpensive to manufacture and install, simple in construction and operation, strong and durable.

Other objects and advantages of my invention will be apparent during the course of the following description.

In the accompanying drawings which form a part of this specification and wherein like characters of reference denote like parts throughout the same,

Figure 1 is an elevation of a furnace having my invention applied thereto,

Figure 2 is a vertical sectional view through the body portion of my attachment,

Figure 3 is a plan view thereof with the lever, clevis and clevis adjusting member removed,

Figure 4 is a transverse section therethrough showing the clevis in position,

Figure 5 is a detail of the end of the thermal element,

Figure 6 is aplan view of the clevis,

Figure 7 is an elevation thereof,

Figure 8 is an elevation of the adjusting bolt, and,

Figure 9 is a horizontal section showing the arrangement of pulleys.

In the drawings, wherein for the purpose .of illustration is shown a preferred embodiment of my invention the numeral 10 designates a furnace having a draft door 11,

and having a check draft 12 arranged on the flue .13. The furnace 10 may be of any suitable construction and type and forms no part of the present invention.

My furnace regulator is mounted on a suitable vertically arranged bracket 1 1 which comprises an upright which is channel shaped and secured to the upper portion 1932; Serial No. 597,826.

of the furnace above the draftdoor 11and preferably in vertical alignment therewith. A flanged body member 15 has itsflanges bolted to the'bracket 1 1 at the upper'end thereof, and extends radially away from the furnace as seen in Figure l. 'A thermal responsive member comprises a tube '16 of brass, copper, aluminum or other metal 'having a relatively high coefficient of expansion which extends through an opening in the 50 bracket 14 and is screw threadedly received in an opening '17 in the body member 15. The tube 16 extends into the upper portion of the furnace for a substantial distance and a rod 18 is rigidly secured to the inner end of the tube as shown in Figure 5 and extends through the tube and into the body member 15 through the opening 17. The rod 18 is of invar steel or other suitable material having a low coefficient of expansion and the end which projects'through the openings 17 is provided with a chisel point19, for a purpose to be hereinafter described;

The body member 15 is provided With a vertical slot 20 extending entirely there'- through and with a horizontal slot 21 also extending therethrough and communicating with the vertical slot 20. A clevis member 22 is arranged in the slot 21and'rests on the bottom thereof, there being a space between 89 the top of the clevis and the top of theslot 21 to allow freedom of movement of the clevis in the slot. A lever 23 extends through the vertical slot 20 and is pivoted at p 2 1 between the arms of the clevis. The lever extends to the top ,of the body member 15 and has a V-shaped depression 2 1 in one edge thereof to engage the chisel point '19. of the rod 18. l The sides of the slot 20 are inclinedaway from the center of the body member above and below the slot 21 "to allow freedom of movement of the lever about the pivot 24. g

The outer portion of the body member is provided with a horizontal screw threaded bore 25 which connects the slot 20 with the end of the body member and receives an adend of the bolt 26 and is spaced from the body member by means of a suitable screw-threaded jam nut or bushing 28. The inner end of the bolt 26 and the outer end of the clevis are provided with cup shaped depressions 25 which engage a ball bearing 29 which spaces the clevis and bolt and allows pivotal move ment of the clevis about the ball 29.

In operation the bolt 26 is moved by means of the wheel 27 to the desired position and the clevis 22 acting as a crosshead will force thg lever 23 against the chisel point 19 of the ro The lever extends a substantial distance below the body member 15 and is bent away from the furnace. A shaft 30 is supported by the bracket 14 in spaced relation thereto and rotatably supports two large pulleys 31 and a small pulley 32, all of which are interconnected to rotate together. The small pulley 32 has a cable 33 wound thereon and connected to the lower end of the lever 23. One of the large pulleys 31 has a cable 34 wound thereon and passes over an idling pulley 35 to the draft door 11 to which it is connected. A cable 36 is wound about the other pulley 31 and passes over idling pulleys 37 to the check draft 12 to which it is connected.

In operation, when the temperature within the furnace lowers, the tube 16 contracts, forcing the rod 18 against the lever 23 and moving it about its pivot. This movement moves the lower end of the lever away from the furnace, thereby rotating the pulley which in turn rotates the large pulleys 31 to close the check draft and open the draft door 11. The movement of the rod 18 is magnified by the lever 23 and is further magnified by the difference between the size of the pulleys 31 and 32. As the temperature within the furnace rises the tube expands and retracts the rod 18 to which it is attached, and allows the weight of the lever 23 and door 11 to close the door 11 and open the check draft 12.

In place of the pulleys: 31 and 32 I may use any other arrangement for transmitting movement of the lever to the doors, such as a segment andpinion connected to the lever or any other suitable means. The arrangement ofthe pulleys to magnify the movement of the lever permits the use of a much shorter lever than would otherwise be possible.

My attachment automatically controls the temperature of the furnace and will maintain an even heat at all times. This attachment may be used with any type of furnace and the tube 16 may be inserted in any convenient portion of the furnace, or in a flue or steam pipe. By providing an even temperature within the furnace the fuel will be burned under the most economical conditions, and dangers from overheating and underheating will be avoided.

The position of the fulcrum 24 may be ad j usted by the hand wheel 27 and the freedom of movement of the clevis about the ball 29 permits self alignment of the clevis with the chisel point 19, thereby permitting a change in the distance between the horizontal planes of the two fulcrum points formed by the bolt 24 and the chisel point 19.

While I prefer to multiply the movement of the lever by means of pulleys or other suitable means, I may omit this mechanism and rely on the length of the multiplying lever 23 to produce'this result.

In applying this attachment to any type of furnace, the only change to the furnace is the bolting of the bracket thereto and the boring of an opening to receive the tube 16. If the attachment cannot be arranged in alignment with the draft door 11 suitable pulleys or the like may be added to bring the cable 34; into alignment with the door.

While I have shown and described the preferred embodiment of my invention, it is to be understood that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

l. The combination with a furnace, of a thermally controlled regulator comprising a body member having a slot therein, a thermally operated member projecting into said slot, a regulating lever extending into said slot and engaging the thermally operated member, and a lever supporting member pivotally connected to said lever at a point spaced from the axis of the thermally operated member and supported in said slot, said lever supporting member being free to move within limits in the direction of the axis of said lever.

2. The combination with a furnace, of a thermally controlled regulator comprising a body member having a slot therein, a thermally operated member projecting into said slot, a regulating lever extending into said slot and engagingthe thermally operated member, a lever supporting member pivotally connected to said lever at a point spaced from the axis of the thermally operated member and supported in said slot, said lever supporting member being free to move in the direction of the axis of said lever, and means to adjust the lever supporting member in a direction at substantially a right angle to the lever axis. 7

The combination with a furnace, of a thermally controlled regulator comprising a body member having a slot therein, a thermally operated member projecting into said slot, a regulatinglever extending into. said slot and engaging the thermally operated member, and a clevis pivotally-supported in said slot and pivotally engaging said lever at a ,point spaced from the plane .of the axis of said thermallyz operated member.

4 l. The combination with a furnace, of a thermally lcontrolled regulator comprising a body. member havinga slot therein, a thermally operated member projecting into said slot, a regulating leverextending into said slot and engaging the thermally operated member, a clevis ,pivotally supported in said slot and pivotally engaging 'said lever ata ated member, and a clevis arranged in said horizontal slot and resting .on the bottom thereof, said clevis pivotally supporting the lever, and said cleviszbeing free to move vertically in said horizontal slot.

(i-The combinationwith a furnace, of a thermally controlled regulator comprising a body member havinga substantially vertical slot extending therethrough, said body member having a substantially horizontal slot ex? tending therethrough ,and communicating with the vertical slot, a thermally operated member extending into said vertical slot, a regulating lever extending through the vertical slot and engaging the thermally operated member, a clevis arranged in said horizontal slot and resting on the bottom thereof, said clevis pivotally supporting the lever. and said clevis being free to move vertically in said horizontal slot, and means to adjust said clevis toward and away from the thermally operated member.

'4'. The combination with a furnace, of a thermally controlled regulator comprising a body member having a substantially vertical slot ext-ending therethrough, said body memher having a substantially horizontal slot extending therethrough and communicating with the vertical slot, a thermally operated member extending into said vertical slot, a regulating lever extending through the vertical slot and engaging the thermally operated member, a clevis arranged in said horizontal slot and resting on the bottom thereof, said clevis pivotally supporting the lever, and said clevis being free to move vertically in said horizontal slot, and an adjusting bolt pivotally engaging said clevis and adapted to adjust said clevis toward and away from the thermally operated member.

8. The combination with a furnace having check valve adraft door andacheckvalvetof aithermally contrQlled regulator comprising a bodymemher having a substantially vertical slot .extending ,therethrough, said bodymember hit/V1 ing a substantially horizontal slotrextending therethrough and communicating ,with the vertical slot, a thermally operated rmember extending into said vertical .slot, a regulating lever extending through the vertical slot and engaging the thermally operated member, a clevis arranged in said horizontal slot (and resting on ,the bottom thereof, said clevis pivota-lly supporting the lever and being free to move vertically in said horizontal slot,=and means operatively connecting the regulating lever with the draftdoor andcheck .valveof the furnace.

9. The combinationwitha furnace having a draft door and acheck valve,.o.f,a thermally controlled regulator comprisinga body member having a substantially vertical slot extending therethrough, said body member having a substantially horizontal slot ex tending therethrough and communicating with the vertical slot, a thermally operated member extending into said vertical slot, a regulating lever extending through the vertical slot and engaging the thermally operated member, a clevis arranged in said horizontal slot and resting on the bottom thereof, said clevis pivotallysupporting the lever and being free to move vertically in said horizontal slot, means-operatively connecting the regulating lever with the draft .door and check valve of thefur'nace, and means to adjusttheclevis toward and away from the thermally operated member. t

10. The combination with a furnace having a draft door and a check valve, of a thermally controlled regulator com-prisinga body member having a substantially vertical slot x e ding thereth ough, s dy mem er having a substantially horizontal slot extend.- ing therethrough and communicating with thevert ical slot, a thermally operated meme extending into said vertical slot, a regulating lever extendingthrough the vertical slot and engaging the thermally operated member, ,a clevis arranged in said horizontal slot andresting on vthe bottom thereof, said clevis pivotally supporting the lever and being free to move vertically in said horizontal slot, and means ,operatively, connecting the regulating lever with the draft door and of the furnace, said thermally operated member comprising a rod having a relatively low coefiicient of expansion and supported in a tube having a relatively high coeflicient of expansion.

11. The combination with a furnace having a draft door and a check valve, ofa thermally controlled regulator comprising a body member having .a substantially vertical slot extending therethrough, said body member having a substantially horizontal slot extending,

therethrough and communicating with the vertical slot, a thermally operated member extending into said vertical slot, a regulating lever extending through the vertical slot and engaging the thermally operated member, a clevis arranged in said horizontal slot and resting on the bottom thereof, said clevis pivotally supporting the lever and being free to move vertically in said horizontal slot, and

means operatively connecting the regulating lever with the draft door and check valve of the furnace, said thermally operated mem ber comprising a rod having a relatively low coefficient of expansion and supported in a tube having a relatively high coefficient of expansion, said tube being supported by said body member and extending into the furnace for a substantial distance.

12. The combination with a furnace, of a thermally controlled regulator comprising a body member having a substantially vertical slot extending therethrough said body memher having a substantially horizontal slot exvtending therethrough and communicating with the vertical slot, a thermally operated member extending into said vertical slot, a reguating lever extending through the vertical slot and engaging'the thermally operated a member, a clevis arranged in said horizontal slot and resting on the bottom thereof, said clevis pivotally supporting the lever, and said clevis being free to move vertically in said horizontal slot, said thermally operated member comprising a rod having a relatively low coefiicient of expansion'and supported in a tube having a relatively high coefficient of expansion. V

13. The'combination with a furnace, of a thermally controlled regulator comprising a body member having a substantially vertical slot extending therethrough, said body member having a substantially horizonal slot extending therethrough and communicating with the vertical slot, a thermally operated member extending into said vertical slot-,a regulating lever extending through the vertical slot and engaging the thermally operated member, a clevis arranged in said horizontal slot and resting on the bottom thereof, said clevis pivotally supporting the lever, and said clevis being free tomove vertically in saidhorizontal slot, said thermally operated member comprising a rod having a relatively lowcoefficient of expansion and supported in a tube having a relatively high coeflicient of expansion, said tube being supported by said body member and extending into the furnace for a substantial distance.

14. The combination with a furnace, of a thermally controlled regulator comprising a body member having a slot therein, a thermally operated member projecting into said slot, a regulating lever extending into said slotand engaging the thermally operated member, and a self adjusting 'crosshead supported in said slot and pivotally engaging said lever at, a point spaced from the axis of said thermally operated member. g

15. The combination with a furnace, of a thermally controlled regulator comprising a body member having a slot therein, a thermally operated member projecting into said slot, a regulating lever extending into said slot and engaging the thermally operated member, a self adjusting crosshead supported in said slot and pivotally engaging said lever at a point spaced from the axis of said thermally operated member, and means to adjust the crosshead toward and away from the thermally operated member.

16. The combination with a furnace, of a thermally controlled regulator comprising a body member, a regulating lever pivotally supported in said body member, a thermally operated member engaging said lever at a pointspaced from the pivot point of the lever and adapted to move the lever about its pivot, and means permitting substantially free movement of the lever pivot in the direction of the leveraxis.

17. The combination with a furnace, of a regulator comprising a body member, a regulating lever pivotally supported in said body member, a thermally operated member engaging said lever at a point spaced from the pivotal point of the lever and adapted to move the lever about its pivot, means permitting free movement within limits of the lever pivot away and towardthe axis of the thermally operated member, and means to adj ust the lever pivot toward and away from the thermally operated member.

In testimony whereof I affix my signature.

' HOWARD F. FERGUSON. 

